Bent-beam stress-corrosion test specimen

G39, Standard Practice for Preparation and Use of Bent-Beam Stress-corrosion Test Specimens, ASTM, West Conshohoken, PA, 1999. 

Fig. 9.4 Bend beams specimen used in constant-deformation test [16]. Reprinted, with permission, from ASTM G 39-99 Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens copyright ASTM International, West Conshohocken, PA.

ASTM G 39, Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens— This describes methods for design, preparation, and use of bent-beam stress-corrosion specimens. This standard covers apparatus for supporting specimens, basic design of a specimen, stress calculations, test conditions, exposure, and inspection techniques. 

Smooth specimens can be stressed by a constant load, by constant strain rate, or by constant deflection, which is the usual procedure. Typical specimens are (a) direct tension specimens, (b) C-ring specimens, (c) U-bend sp>ecimens, (d) bent beam specimens, and special techniques for weldments (see ASTM G 49, Practice for Preparation and Use of Direct Tension Stress-Corrosion Test Specimens ASTM G 38, Practices for Making and Using C-Ring Stress-Corrosion Test Specimen ASTM G 30, Practice for Making and Using U-Bend Stress-Corrosion Test Specimens ASTM G 39, Practice for Prep>aration and Use of Bent-Beam Stress-Corrosion Test Specimens and ASTM G 58, Practice for the Preparation of Stress-Corrosion Test Specimens for Weldments, respectively). 

FIG. 28-18 Specimens for stress-corrosion tests, (a) Bent beam, (h) C ring, (c) U Lend, (d) Tensile, (e) Tensile, (f) Tensile, (g) Notched C ring, (h) Notched tensile. ( ) Precracked, wedge open-loading type. (/) Precracked, cantilever beam. [Chem. Eng., 78, 159 (Sept. 20 1971).]... 

Corrosion of metals and alloys stress corrosion testing. Part 2 Bent-beam specimens Corrosion of metals and alloys. Part 3 U-bend specimens... 

Corrosion of Metak and Alloys-Stress Corrosion Testing-Part 1 Preparation tmd Use of Bent-Beam Specimens... 

Corrosion of Metals and AUoys—Stress Corrosion Testing— Part 2 Preparation and Use of Bent Beam Specimens, ISO 7539-2, 1989. 

Corrosion of metals and alloys—Stress corrosion testing—Part 2 Preparation and use of bent-beam specimens... 

Considerable attention has been devoted to the interaction between mechanical loading and corrosion phenomena. Corrosion fatigue has been investigated with sinusoidal loading [26] and with force patterns more representative of actual in vivo stresses [27]. Both specimens of simple geometry [28] and actual prosthetic devices [29] have been tested. SCC has been studied using U-bend [30], stress ring [37], bent beam [37], and fracture mechanics [32] type... 

Therefore, a new stress corrosion cracking test method was developed (Creviced Bent Beam CBB test), which considers the crevice effect as well as factors B, C and D above. Bend test specimens with an artificial crevice made from graphite wool (more sensitive than those made from PETE and especially metal-metal) were tested (both welded and non-welded but sensitised at 600 C/2 h) in high purity water with 0.2 pS/cm, oxygen saturated, chloride < 0.1 mg/1, pH S.8-6.2 at 250 C. For more than 20 steel specimens with different carbon contents (which are responsible for various susceptibilities to sensitisation) one obtains very clear conclusions from 20 specimens each of them showed stress corrosion cracking after only 24 hours, so long as the carbon content lied in the range 0.06-0045%. In the process cracks with... 

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